package com.hmdp.utils;

import lombok.AllArgsConstructor;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
@AllArgsConstructor
public class RedisIdWorker {
	/**
	 * 开始时间戳，2022年1月1日0点0时0分0秒
	 */
	private static final long BEGIN_TIMESTAMP = 1640995200L;
	/**
	 * 序列号的位数
	 */
	private static final int COUNT_BITS = 32;

	private final StringRedisTemplate stringRedisTemplate;

	public long nextId(String keyPrefix) {//keyPrefix可以理解为业务的前缀，主要用来区分不同业务的id
		// 1.生成时间戳
		LocalDateTime now = LocalDateTime.now();
		long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
		long timestamp = nowSecond - BEGIN_TIMESTAMP;

		// 2.生成序列号
		// 2.1.获取当前日期，精确到天
		String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
		// 2.2.自增长
		long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

		// 3.拼接并返回
		return timestamp << COUNT_BITS | count;
	}
}